MasterHarper of Pern showed improvement in plotting and characterization compared to the few books published prior. I think this was largely helped by the fact that it's a prequel to Dragonflight, so all of the big plot elements have already been established.
Robinton is a major character found in the first few Pern novels and any story that takes place in the Ninth Pass timeline of Pern. He's the MasterHarper, in charge of Harper Hall, has a fondness for red wine and friendship, and is a talented and beloved leader. MasterHarper of Pern provides background on his upbringing and the events leading up to Lord Fax's invasions in the northern holds of Pern, detailed in the beginning of Dragonflight.
This is a character that never seemed particularly divisive among fans, considering other characters of Pern have gotten criticized for their more traditional treatment of women.
About half of the book details Robinton's youth, primarily focused on his poor relationship with his father, Petiron. He is very close with his mother, Merelan. I got Freudian echoes in many of the scenes between Robinton and Merelan. I am highly doubtful McCaffrey intended anything in that manner, but their mother-son relationship felt off to me.
Additionally, I got the impression that Petiron didn't like Robinton because he wanted Merelan all to himself, whereas later in the book it tries to frame it as Petiron was jealous of Robinton's musical abilities. Petiron didn't really act that way. Didn't try to sabotage Robinton's musical abilities or career. It was also weird how Robinton and Petiron all of a sudden came to terms in one paragraph.
The latter half of the book has Robinton's first serious romance, with Kasia, and his dealings as a journeyman harper. The dragon rider F'lon (father to F'lar and F'nor of Dragonflight) is friends with Robinton since youth, and he pops in and out of the storyline.
Eventually, Robinton does become MasterHarper, but it's close to the end. The last parts of this book run parallel to Dragonflight. In one way, it was interesting to have a different pov of the Ruathan Hold scene, but on the other hand, seemed way too convenient because it didn't need much originality.
Overall, I though the pacing was better that Dragonseye and The Dolphins of Pern. Probably because it was truly focused on Robinton, and in general Robinton tends to be involved in a lot of politics and interesting events.
Because much of this plot is already established, many of the elements don't have any surprise. We know Robinton will become MasterHarper and we know what will happen to Fax. We also know Thread is going to return. It doesn't give a whole lot of originality, but I liked reading about Robinton.
There were some scenes early in the book, with Halanna, a young singer, that didn't sit so right with me. I chalk it up to McCaffrey's old-fashioned ideas about how to deal with strong-willed women that's pervaded the whole series, even though in the later published books it has lightened up. Essentially, Halanna is being a brat. Petiron slaps her. She calls her dad and brothers because she's mad, and then her dad spends three days hitting her until she decides to act right, and her brothers agree that's the only way to make her behave.
Lastly, MasterHarper of Pern reneges on prior world-building when it comes to women as harpers. Robinton's mother is a MasterSinger, and there are multiple women acting as harpers. However, over about two generations, all the women have disappeared, at the start of the ya Harper Hall trilogy featuring Menolly. There's a few sloppy excuses: Robinton tried to find girls but couldn't, and an older female harper just wanted to attend to domestic duties. Considering Harper Hall fights to save traditions, it doesn't make sense. Why break with the world-building for this book?